Synthesis and Characterization of Iron Bispyridine Bisdicyanamide, Fe[C(5)H(5)N](2)[N(CN)(2)](2)

Fe[C(5)H(5)N](2)[N(CN)(2)](2) (1) was synthesized from a reaction of stoichiometric amounts of NaN(CN)(2) and FeCl(2)·4H(2)O in a methanol/pyridine solution. Single-crystal and powder diffraction show that 1 crystallizes in the monoclinic space group I2/m (no. 12), different from Mn[C(5)H(5)N](2)[N(CN)(2)](2) (P2(1)/c, no. 14) due to tilted pyridine rings, with a = 7.453(7) Å, b = 13.167(13) Å, c = 8.522(6) Å, β = 114.98(6)° and Z = 2. ATR-IR, AAS, and CHN measurements confirm the presence of dicyanamide and pyridine. Thermogravimetric analysis shows that π-stacking interactions of the pyridine rings play an important role in structural stabilization. Based on DFT-optimized structures, a chemical bonding analysis was performed using a local-orbital framework by projection from a plane-wave basis. The resulting bond orders and atomic charges are in good agreement with the expectations based on the structure analysis. SQUID magnetic susceptibility measurements show a high-spin state Fe(II) compound with predominantly antiferromagnetic exchange interactions at lower temperatures.